Sander



1.. v.. GROVER 3,429,077

Feb. 25, 1969 SANDER Filed April 15. 1966 1 N VEN TOR.

Z Y/vp aw L Gem/eve )rrmafl, b.4446. ATTORNEYS 1) I United States Patent 3,429,077 SANDER Lyndon V. Grover, 341 W. Arden Blvd, Glendale, Calif. 91203 Filed Apr. 15, 1966, Ser. No. 542,811 U.S. Cl. 51-148 Int. Cl. 1324b 21/00, 25/00 6 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a belt sander.

Although the principles of the present invention may be included in various sanders, a particularly useful application is made in a sander which is constructed to be supported on a table, and which is particularly adapted to employ abrasive belts of various lengths.

The present invention includes an elongated belt-tensioning device of such construction as to enable the use of a wide range of belt lengths on the sander, each of such belts being supported on its back side for substantially the entire effective length along one leg thereo the means which provides such support being effective for substantially any length of belt.

Accordingly, it is an object of the present invention to provide an improved belt-type sander.

A further object of the present invention is to provi le 2. belt-type sander which can accommodate a wide range of belt lengths.

A still further object of the present invention is to provide backing means for a belt sander which is effective for substantially the entire length of a leg thereof.

Yet a further object of the present invntion is to provide a belt sander which may be adjusted for various lengths of belt without altering the backing support provided therefor.

Many other advantages, features and additional objects of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying drawing in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of illustrative example.

On the drawing The drawing is a cross sectional view of a sander of the belt type constructed in accordance with the principles of the present invention.

As shown on the drawing The sander, generally indicated by the numeral 10, includes a base 11, a first arm 12, a second arm 13, and an elongated belt-tensioning device 14. The first arm 12 is secured at one end in a pivotal manner to the base 11 for adjustment about the axis of a shaft 15, the position of which may be fixed by means of a screw 16. Rotatably supported about the shaft 15, there is a first pulley 17 to which there is secured a driving pulley 18. The driving pulley 18 may be driven by a motor-driven belt (not shown). The pulley 17 may be directly driven by a motor.

The second arm 13 has a second pulley 19 rotatably 3,429,377 Patented Feb. 25, 1969 supported on a free end thereof. The first arm 12 and the second arm 13 are provided with a pivotal connection therebetween, the same being indicated by the numeral 20. A third pulley 21 is disposed on one of the arms, namely on one end of the arm 13 adjacent to the pivotal connection 20.

An endless abrasive belt 22 extends about the pulleys 17, 19, and 21, so that when one of these pulleys is rotatably driven, the endless belt 22 is similarly rotatably driven about these three pulleys.

In order to maintain the arms 12, 13 at such an angle as to provide the proper tension to the endless belt 22, there is provided the elongated belt-tensioning device 14 which is of adjustable length. The device 14 has its opposite ends 23, 24 respectively secured to the arms .12, 13 at points disposed between the pivotal connection 20 and the first and second pulleys 17, 19.

More specifically, the arm 12 has a series of recesses or wells 25 cast integral therewith at the bottom of a channel, while the arm 13 has a series of V-groove recesses or ratchet teeth 26 similarly disposed and cast integral therewith on the inside of a channel, the recesses 25, 26 extending along the length of said arms 12, 13 in such channels, and each series of recesses 25, 26 being directed toward the other arm 13, 12. The opposite ends 23, 24 of the belt tensioning device 14 are pivotally supported in the recesses 25, 26 respectively.

The recesses 25 of the well type comprise narrow semi-circular sockets which receive the circular end 23 of an eye-bolt 27, while the recesses or V-grooves 26 receive the end 24 of a sleeve 28, the end 24 comprising a cone point. A nut 29 is carried by the eye-bolt 27 and engages the end of the sleeve 28. The nut position enables compensation for various belt lengths.

As the ends 23, 24 of the belt-tensioning device 14 are moved to various recesses 25, 26, the belt-tensioning device is enabled to accommodate a wide range of belt lengths. In a prior device, the size of belt lengths which could be accommodated varied by one and one-half inches. With the present structure, the range of belt length variations that can be accommodated is at great as ten inches.

The side of the arm 13 which is opposite to the recess-defining means 26 comprises an oppositely directed flat surface 30 which comprises a backer for the abrasive belt 22. The arm 13 carries an adjustably positioned workpiece support 31 against which a workpiece may engage. The backing surface 30 extends substantially all the way to the pulley 21 leaving substantially no gap between the end of such surface and the pulley 21. Thus the abrasive belt 22 is provided with backing means all the way from the work sup-port 31 to the pulley 21.

In that the pulley 21 is carried by the second arm 13, and the pivotal connection 20 is disposed on the second arm between the pulleys 19 and 21, no matter how great the adjustment of the belt-tensioning device 14 may be, the belt 22 remains backed-up by the backing surface 30.

Thus according to the present invention, belts having a wide range of length may be employed, the belt-tensioning device being of such construction as to accommodate such wide range of belts, and the geometry of the structure being such that even though there is a wide range of adjustment about the pivotal connection 20, the belt 22 remains backed up by the supporting surface 30, such backing extending all the way up to the pulley 21.

Although various minor modifications might be suggested by those versed in the art, it should be understood that I wish to embody within the scope of the patent warrented hereon all such embodiments as reasonably and properly come within the scope of my contribution to the art.

I claim as my invention:

1. A sander including in combination:

(a) a base;

(b) a first arm secured at one end to said base, said first arm having a first pulley at said one end;

() a second arm having a free end supporting a second pulley, said second arm having a belt backing surface for supporting a belt in any position of said second arm;

(d) a third pulley carried by said second arm;

(e) a pivotal connection between said arms at the other end of said first arm and spaced from the other end of said second arm between said second and said third pulleys;

(f) an endless abrasive belt extending about said pulleys;

g) means for driving one of said pulleys; and

(h) an adjustable belt-tensioning device supported on said arms and acting at points disposed between said pivotal connection and said first and second pulleys.

2. A sander according to claim 1, in which said beltbacking surface extends along the length of said second arm and spans substantially the entire distance between said pivotal connection and said third pulley.

3. A sander including in combination:

(a) a base;

(b) a first arm secured at one end to said base, said first arm having a first pulley at said one end;

(c) a second arm having a free end supporting a second pulley;

((1) means along the length of each of said arms defining a series of recesses in each of said arms and directed toward the recesses of the other of said arms;

(e)/a pivotal connection between said arms at their other ends, and a third pulley disposed on one of said arms adjacent to said connection;

(f) an endless abrasive belt extending about said pulleys;

(g) means for driving one of said pulleys; and

(h) an elongated belt-tensioning device of adjustable length having its opposite ends pivotally supported on said arms and each end respectively received in one of said recesses.

4. A sander according to claim 3, wherein one of the ends of said elongated belt-tensioning device comprises a circular portion, and wherein said recesses receiving said circular portion comprise semicircular sockets.

5. A sander according to claim 1, having means along the length of at least one of said arms defining a series of semicircular sockets directed toward the other of said arms, one end of said belt-tensioning device comprising a circular portion supported in one of said sockets.

6. A sander according to claim 3, wherein said third pulley is carried by said second arm, said pivotal connection being disposed at the end of said first arm remote from said first pulley, and between said second and said third pulleys on said second arm, and a belt-backing surface on said second arm for supporting a belt in any position of said second arm;

References Cited UNITED STATES PATENTS 788,287 4/ 1905 Swanson. 2,470,615 5/1949 Grover 51-148 X 3,093,170 6/1963 Thayer 51-148 X LESTER M. SWINGLE, Primary Examiner.

JAMES F. MCKEQWN, Assistant Examiner. 

